Use empty() instead of comparing against new string.

src/vw/BundleAdjustment/ControlNetwork.cc

@@ -170,9 +170,9 @@ namespace ba {
       f << "      EphemerisTime  = " << m_ephemeris_time << "\n";
     if ( m_diameter > 0 )
       f << "      Diameter       = " << m_diameter << "\n";
-    if ( m_date_time != "" )
+    if ( !m_date_time.empty() )
       f << "      DateTime       = " << m_date_time << "\n";
-    if ( m_chooserName != "" )
+    if ( !m_chooserName.empty() )
       f << "      ChooserName    = " << m_chooserName << "\n";
     if ( m_ignore )
       f << "      Ignore         = True\n";
@@ -210,7 +210,7 @@ namespace ba {
       // Cleaning out any tokens that are just ""
       for(std::vector<std::string>::iterator iter = tokens.begin();
           iter != tokens.end(); ++iter ) {
-        if ( (*iter) == "" ) {
+        if ( (*iter).empty() ) {
           iter = tokens.erase(iter);
           iter--;
         }
@@ -446,7 +446,7 @@ namespace ba {
       // Cleaning out any tokens that are just ""
       for(std::vector<std::string>::iterator iter = tokens.begin();
           iter != tokens.end(); ++iter ) {
-        if ( (*iter) == "" ) {
+        if ( (*iter).empty() ) {
           iter = tokens.erase(iter);
           iter--;
         }
@@ -634,7 +634,7 @@ namespace ba {
     // Making sure all the control points have unique IDs
     size_t cpcount = 0;
     BOOST_FOREACH( ControlPoint& cp, m_control_points ) {
-      if ( cp.id() == "Null" || cp.id() == "" ) {
+      if ( cp.id() == "Null" || cp.id().empty() ) {
         std::ostringstream ostr;
         ostr << std::setw(9) << std::setfill('0') << cpcount;
         cp.set_id( ostr.str() );
@@ -698,7 +698,7 @@ namespace ba {
       // Cleaning out any tokens that are just ""
       for(std::vector<std::string>::iterator iter = tokens.begin();
           iter != tokens.end(); ++iter ) {
-        if ( (*iter) == "" ) {
+        if ( (*iter).empty() ) {
           iter = tokens.erase(iter);
           iter--;
         }

src/vw/Cartography/GeoReference.cc

@@ -671,7 +671,7 @@ double GeoReference::test_pixel_reprojection_error(Vector2 const& pixel) {
 
     // Apply projcs override if it was specified
     std::string projcs_name = this->get_projcs_name();
-    if (projcs_name != "")
+    if (!projcs_name.empty())
       gdal_spatial_ref.SetProjCS(projcs_name.c_str());
 
     // For perfect spheres, we set the inverse flattening to

src/vw/FileIO/DiskImageResourceGDAL.cc

@@ -361,7 +361,7 @@ namespace vw {
 
     m_options = user_options;
 
-    if (m_options["PREDICTOR"] == ""){
+    if (m_options["PREDICTOR"].empty()){
       // Unless predictor was explicitly set, use predictor 3 for
       // compression of float/double, and predictor 2 for integers,
       // except whose size is one byte, as for those compression makes

src/vw/FileIO/DiskImageResourceRaw.cc

@@ -51,7 +51,7 @@ void DiskImageResourceRaw::close() {
 // Factory functions required by DiskImageResource.cc
 DiskImageResource* DiskImageResourceRaw::construct_open( std::string const& filename ) {
   std::string dim_file = find_associated_spot5_dim_file(filename);
-  if (dim_file == "") 
+  if (dim_file.empty()) 
     vw_throw( ArgumentErr() << "Could not find .DIM file for: " << filename);
 
   return DiskImageResourceRaw::construct(filename, image_format_from_spot5_DIM(dim_file));

src/vw/FileIO/FileUtils.cc

@@ -108,7 +108,7 @@ bool vw::has_spot5_extension(std::string const& image_file, std::string const& c
   if ((image_ext == ".bip") || (image_ext == ".bil") || (image_ext == ".bsq"))
     return true;
   // If no camera file was provided it cannot be a Spot5 file
-  if ((camera_file == "") || (camera_file == image_file))
+  if ((camera_file.empty()) || (camera_file == image_file))
     return false;
   // The Spot5 file is the last thing we check
   const std::string camera_ext = vw::get_extension(camera_file);

src/vw/FileIO/KML.cc

@@ -84,9 +84,9 @@ namespace vw {
   void KMLFile::enter_folder( std::string name,
                               std::string desc ) {
     open_bracket("Folder");
-    if ( name != "" )
+    if ( !name.empty() )
       m_output_file << m_tab << "<name>"<< name <<"</name>\n";
-    if ( desc != "" )
+    if ( !desc.empty() )
       m_output_file << m_tab << "<description>"<< desc <<"</description>\n";
   }
 
@@ -104,12 +104,12 @@ namespace vw {
                                   double altitude,
                                   bool extrude ) {
     open_bracket("Placemark");
-    if ( name != "" )
+    if ( !name.empty() )
       m_output_file << m_tab << "<name>"<< name <<"</name>\n";
-    if ( description != "" )
+    if ( !description.empty() )
       m_output_file << m_tab << "<description>"
                     << description << "</description>\n";
-    if ( style != "")
+    if ( !style.empty())
       m_output_file << m_tab << "<styleUrl>#"<<style<<"</styleUrl>\n";
     open_bracket("Point");
     if ( extrude )
@@ -125,9 +125,9 @@ namespace vw {
                              std::string name,
                              std::string style ) {
     open_bracket("Placemark");
-    if ( name != "" )
+    if ( !name.empty() )
       m_output_file << m_tab << "<name>"<< name <<"</name>\n";
-    if ( style != "")
+    if ( !style.empty())
       m_output_file << m_tab << "<styleUrl>#"<<style<<"</styleUrl>\n";
     open_bracket("LineString");
     m_output_file << m_tab << "<altitudeMode>absolute</altitudeMode>\n";
@@ -157,9 +157,9 @@ namespace vw {
     double heading = angles(0)*180/M_PI, tilt = angles(1)*180/M_PI, roll = angles(2)*180/M_PI;
 
     open_bracket("Placemark");
-    if ( name != "" )
+    if ( !name.empty() )
       m_output_file << m_tab << "<name>"<< name <<"</name>\n";
-    if ( description != "" )
+    if ( !description.empty() )
       m_output_file << m_tab << "<description>"
                     << description << "</description>\n";
 
@@ -228,7 +228,7 @@ namespace vw {
       close_brackets(1);
     }
     open_bracket("IconStyle");
-    if (color_hex != "" )
+    if (!color_hex.empty() )
       m_output_file << m_tab << "<color>" << color_hex << "</color>\n";
     m_output_file << m_tab << "<scale>" << scale << "</scale>\n";
     open_bracket("Icon");
@@ -243,7 +243,7 @@ namespace vw {
     m_output_file << m_tab << "<Style id=\"" << id << "\">\n";
     m_tab.count++;
     open_bracket("LineStyle");
-    if (color_hex != "" )
+    if (!color_hex.empty() )
       m_output_file << m_tab << "<color>" << color_hex << "</color>\n";
     m_output_file << m_tab << "<width>" << width << "</width>\n";
     close_brackets(1);
@@ -288,7 +288,7 @@ namespace vw {
   // Open / Close Stuff
   void KMLFile::open_kml() {
     std::ostringstream path;
-    if ( m_directory != "" )
+    if ( !m_directory.empty() )
       path << m_directory << "/";
     path << m_filename;
     fs::path kml_path( path.str() );

src/vw/Geometry/dPoly.cc

@@ -1149,7 +1149,7 @@ void dPoly::writePoly(std::string filename, std::string defaultColor){
 
     string layer = "";
     if (pIter < (int)m_layers.size()) layer = m_layers[pIter];
-    if (layer != "") layer = " ; " + layer;
+    if (!layer.empty()) layer = " ; " + layer;
 
     bool isPolyClosed = true;
     if ( pIter < (int)m_colors.size() ) isPolyClosed = m_isPolyClosed[pIter];

src/vw/Mosaic/DiskImagePyramid.h

@@ -261,7 +261,7 @@ namespace vw { namespace mosaic {
     m_top_image_max_pix(top_image_max_pix),
     m_nodata_val(std::numeric_limits<double>::quiet_NaN()) {
 
-    if (base_file == "")
+    if (base_file.empty())
       return;
 
     if (subsample < 2) {

src/vw/tools/detect_water.cc

@@ -109,11 +109,11 @@ int main(int argc, char **argv) {
     return -1;
   }
 
-  if ((dem_path != "") && (!radar_mode))
+  if ((!dem_path.empty()) && (!radar_mode))
     std::cout << "Warning: DEM file is only used when mode is 'sentinel1'\n";
 
   // If a DEM file was provided, make sure it actually exists before we start doing any processing.
-  if ((dem_path != "") && !boost::filesystem::exists(dem_path)) {
+  if ((!dem_path.empty()) && !boost::filesystem::exists(dem_path)) {
     std::cout << "Error: Provided DEM file not found!\n";
     return -2;
   }

src/vw/tools/georef.cc

@@ -128,7 +128,7 @@ int main( int argc, char *argv[] ) {
     read_georeference( georef, file_resource );
   }
 
-  if ( georef.proj4_str() == "" ) georef.set_well_known_geogcs("WGS84");
+  if ( georef.proj4_str().empty() ) georef.set_well_known_geogcs("WGS84");
   if( manual || georef.transform() == identity_matrix<3>() ) {
     if( manual ) {
       vw_out() << "Using manual Plate Carree coordinates: ";

src/vw/tools/image2qtree.h

@@ -156,7 +156,7 @@ struct Options {
       VW_ASSERT(input_files.size() == 1,
                 vw::tools::Usage() << "Non-georeferenced images cannot be composed");
     if (mode == "CELESTIA" || mode == "UNIVIEW")
-      VW_ASSERT(module_name != "",
+      VW_ASSERT(!module_name.empty(),
                 vw::tools::Usage() << "Uniview and Celestia require --module-name");
 
     if (proj.type == "NONE")
@@ -394,7 +394,7 @@ void do_mosaic(const Options& opt, const vw::ProgressCallback *progress) {
 
   if (opt.tile_size > 0)
     quadtree.set_tile_size(opt.tile_size);
-  if (opt.output_file_type != "")
+  if (!opt.output_file_type.empty())
     quadtree.set_file_type(opt.output_file_type);
 
   // This box represents the input data, shifted such that total_bbox.min() is

src/vw/tools/image2toast.cc

@@ -105,7 +105,7 @@ int main(int argc, char **argv) {
     return 1;
   }
 
-  if( output_file_name == "" )
+  if( output_file_name.empty() )
     output_file_name = fs::path(image_files[0]).replace_extension("toast").string();
 
   if( tile_size <= 0 || tile_size != pow(2.,floor(log((double)tile_size)/log(2.))) ) {

src/vw/tools/radar.h

@@ -853,7 +853,7 @@ void sar_martinis(std::string const& input_image_path, std::string const& output
   }
 
 
-  if (dem_path == "") {
+  if (dem_path.empty()) {
     // Handle the case where a DEM was not provided
 
     std::cout << "No input DEM file provided, finishing calculations without one.\n";

src/vw/tools/slopemap.cc

@@ -344,7 +344,7 @@ int main( int argc, char *argv[] ) {
     return 1;
   }
 
-  if( opt.output_prefix == "" )
+  if( opt.output_prefix.empty() )
     opt.output_prefix=fs::path(opt.input_file_name).replace_extension().string();
 
   //checking strings
@@ -355,7 +355,7 @@ int main( int argc, char *argv[] ) {
     algorithm_string == "sa" ||
     algorithm_string == "planefit" ||
 
-    algorithm_string == "" ) ) { //it's okay if it isn't set?
+    algorithm_string.empty() ) ) { //it's okay if it isn't set?
     vw_out() << "Unknown opt.algorithm: " << algorithm_string << ". Options are : [ horn, fh, sa, planefit ]\n";
     exit(0);
   }

src/vw/tools/undistort_image.cc

@@ -422,7 +422,7 @@ int main( int argc, char *argv[] ) {
 
   output_nodata_value_was_set = vm.count("output-nodata-value");
 
-  if (input_file_name == "" || camera_file_name == "" || output_file_name == "")
+  if (input_file_name.empty() || camera_file_name.empty() || output_file_name.empty())
     vw_throw(ArgumentErr() << "Not all inputs were specified.\n" << desc << "\n");
 
   vw::create_out_dir(output_file_name);